Field of the Invention
The present invention relates, in general, to a method for controlling an electric oil pump (EOP) of a torque assist automated manual transmission (AMT) and, more particularly, to a technique capable of providing an optimized operation method of an EOP by using a multi-plate wet clutch when performing shifting from a low speed or gear where torque fluctuation is large due to use of a torque assist ATM.
Description of Related Art
In an automated manual transmission (AMT), shifting is automatically performed by an actuator during driving of a vehicle, thus providing driving convenience that is similar to that in an automatic transmission and contributing to improvement in the fuel efficiency of the vehicle owing to the mechanical efficiency of power transmission, which is superior to that of the automatic transmission.
Such an AMT is a device in which by using an electro-hydraulic actuator in addition to an existing manual transmission, shifting is automatically performed based on gear control through a transmission control unit (TCU) without assistance from the vehicle driver.
FIG. 1 schematically illustrates a torque assist AMT system of a related art to which the present invention is applied as well. Torque transferred from an engine 1 is selectively transferred to the transmission through intermittence of a dry clutch 3 and an assist clutch 5, and through the intermittence of the dry clutch 3, first, third, fourth, and fifth speeds or gears are formed, and through the intermittence of the assist clutch 5, a second gear is formed.
For example, during low-gear driving where the first or third shifting gear is formed, shifting to the second gear may be performed through control of handover between the dry clutch 3 and the assist clutch 5, preventing a torque drop occurring during shifting to the second gear and thus preventing torque interruption during shifting.
The assist clutch 5 is a wet clutch capable of forming oil pressure through an EOP 11, and applies oil pressure to the assist clutch 5 through hydraulic control with a solenoid valve 13. The assist clutch additionally maintains the applied oil pressure.
Meanwhile, a torque assist AMT system performs double-clutch shifting by using a wet clutch (a multi-plate wet clutch) from a low gear where torque fluctuation is large, and performs single-clutch shifting merely using a wet clutch at a high gear where torque fluctuation is relatively small. Thus, in low-gear shifting the EOP is used such that optimized driving of the EOP is a critical factor determining the efficiency and fuel efficiency of the torque assist AMT system.
Therefore, the present invention provides a method for controlling an EOP for a torque assist AMT to achieve optimized driving of the EOP in low-gear shifting.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.